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Four Reasons Behind Your ARTEX ELT-4000 4-Flash Fault Failure

May 2024


We recently encountered a challenging situation while troubleshooting a 4-Flash Fault following a customer’s upgrade from the discontinued ARTEX ELT-3000 HM to the ARTEX ELT-4000 HM on multiple helicopters. Four potential causes emerged. While each could cause the 4-Flash Fault independently, this particular scenario had all four.  

The Situation

During the upgrade installation, our customer used the existing PAs (Programming Adaptors) from their ELT-3000 installation. It is important to note that these PAs are intended for use with both the ELT-3000 and ELT-4000, sharing the same part number, but require different programming for installation.

Fault Cause #1: Programming Adaptors
Immediately, we discovered the PA programming was overwriting the ELT-4000 options, stating that it was an ELT-3000 with the 243 MHz selected. Notably, the ELT-4000 emits signals at 121.5 and 406 MHz, not 243 MHz. However, even after removing the PA from the installation, our 4-Flash Fault issues continued.

Fault Cause #2: Battery Packs
Further investigation revealed that some of the battery packs manufactured initially could trigger a 4-Flash Fault. ACR Electronics, the battery manufacturer, has since added enhanced testing procedures during production, beginning with battery S/N 1007566-001. NOTE: Only a small percentage of the existing battery packs may cause sporadic failures. If your battery pack does not exhibit this error, replacement isn’t necessary.  

We then examined four complete ELTs with battery packs sent to the Duncan Aviation Components Repair shop in Lincoln, Nebraska. After thorough testing and reprogramming to the appropriate airframes, two units worked correctly and were returned to the customer. The two remaining units were sent to ACR Electronics for warranty repairs and new batteries.

Unfortunately, even after reinstalling these units, our customer continued to experience a 4-Flash Fault.

Fault Causes #3: Coax cables
Continued discussions with our customer led to having a technician acquire test equipment to test the ELTs while on the airframe at their facility. This additional testing identified that the RG400 coax cable installed in the airframe wasn't compatible with the ELT-4000 setup as it was with the ELT-3000 installation.

To visually determine what coax cable you have installed, the RG400 coax has a stranded center conductor as opposed to the solid center conductor in the RG142.

Fault Cause #4: Antenna
The upgrade installation to the ELT-4000 does not require replacing the existing antenna. However, while testing the ELTs on the airframe, a defective antenna was discovered that could cause a 4-Flash Fault error.

Replacing the coax cable with the recommended RG142 and swapping out the defective antenna was the final fix that eliminated the 4-Flash Fault error.

After learning about all of these potential causes, our customer was then able to troubleshoot and install the remaining upgrades to his helicopter fleet. They have since completed a total of seven installations with no new issues.

In Summary:

When upgrading your ELT, we highly recommend you do the following:

  1. Always confirm the ELT and PA Programming Options before installation.
    • When using a PA during installation, the ELT Options must be set as PA Enabled.
    • If no PA is installed, the ELT Options must be set as PA Disabled.
  2. If you encounter 4-Flash Fault issues with an ELT-4000, send it to Duncan Aviation for thorough evaluation and testing to identify whether the problem lies with the ELT or the battery pack. We can assist with locating a warranty replacement battery if necessary.
  3. Double-check that the coax being used is RG142.
  4. Confirm that the antenna is not defective.

Other ARTEX ELT updates

Duncan Aviation Component Services is now authorized to work on the ARTEX ELT-345 product line. We are beginning to acquire test sets and equipment. Contact a Duncan Aviation Customer Account Rep to confirm before sending your ELT-345. For technical support, call 1.800.562.6377.